Hi Fernando,
Attributes can be used to change product configuration and can affect its price. For example, Colour, and Size can be attributes applied to the "t-shirt" product. Every combination of attribute values could have its own SKU, price, stock, etc.
Properties can be used to better describe products. For example, the Country of Origin, and Material could be properties applied to the "t-shirt" product.
Both Properties and Attributes could be used to create Filters.
Please refer to our Wiki here:
https://www.oscommerce.com/wiki/Managing_Properties
https://www.oscommerce.com/wiki/Managing_Attributes